Preheat flame control



Nov. 28, 1961 B. H. ACOMB .PREHEAT FLAME CONTROL Filed Sept. 18, 1958FUEL GAS PRE HEAT OX Y6 EN CUTTING OXYGEN INVENTOR BYRGN H ACOMB 5614/TURNEY United States Patent 9 3,010,468 PREHEAT FLAME CONTROL Byron H.Acomb, Watchung, N.J., assignor to Union Carbide Corporation, acorporation of New York Filed Sept. 18, 1958, Ser. No. 761,805 7 Claims.(Cl. 137114) This invention relates to an improved preheat flame controlapparatus for an oxygen cutting blowpipe, and more particularly concernsan improved control for automatically reducing the heating ability of apreheat flame when oxygen cutting gas is passed through the blowpipe.

In cutting metal with a stream of oxidizing gas, oxygen and a fuel gassuch as acetylene are normally supplied to blowpipe to give asatisfactory preheat flame. The preheat flame heats the metal to itskindling temperature after which the cut is started by directing astream of cutting oxygen at the heated spot. During the cuttingoperation, the preheating flame remains burning to make uptor the heatthat is lost due to radiation, conduction, and the like. For rapidstarts it is desirable to have a large preheating flame. However, oncethe flow of cutting gas has started, the quantity of preheating gasesshould be reduced in order to avoid meltover of the kerr top edges.

Heretofore, the usual means for switching from a high preheat flame to alow preheat flame involved a lever or switch which had to bemanuaily'actuated by the operator. Not only is this inconvenient for theoperator to operate, but in multiple blowpipe setups where each preheatflame has to be individually throttled, by the time the last preheatflame is adjusted, the work has progressed a considerable distance.

it is therefore an important object of the present invention to providean improved preheat flame control for a blowpipe to produce a highpreheat flame when the flow of cutting oxygen is shut off and a lowpreheat flame upon resumption of cutting oxygen flow.

Another object of the present invention is to provide for a blowpipe animproved oxygen control mechanism capable of producing a high preheatflame when the flow of cutting oxygen is shut ofl and a low preheatflame upon resumption of cutting oxygen flow, there being a substantimlyconstant pressure drop in the oxygen cutting hose during the flow ofcutting oxygen through the oxygen control mechanism regardless of thequantity ofcutting oxygen flowing therethrough.

Yet another object of the present invention is to provide novel means ina preheat flame control apparatus for an oxygen cutting blowpipe whichprovides a substantially constant pressure drop of cutting oxygen inmechanism embodying the principles of the invention, and

FIGURE 2 is an enlarged sectional elevational view of the controlmechanism of the invention.

In FIGURE 1 is shown a diagrammatic flow sheet of an oxygen cuttingblowpipe installation embodying the features of the invention andcomprising a gas control device 19 which admits cutting oxygen from asource of high pressure cutting oxygen 12 and preheat oxygen from asource of high pressure preheat oxygen 14, and controls the flow ofpreheat oxygen to a cutting torch or blowpipe "ice 16. Regulators 13a,13b, and 130 control the flow of cutting oxygen, preheat oxygen, andfuel gas, respectively. The blowpipe 16 is preferably a 3-hose blowpipeof the fuel injection type, although other blowpipes suchas the mixertype are also susceptible of use in connection with the invention.

The present invention resides in the employment of a novel controlmechanism for automatically adjusting the flow of preheat oxygen, makingit possible to change from a high flow preheat flame when cutting oxygenis not consumed, to a low preheat flame when the cutting oxygen is beingconsumed.

Referring to FIGURE 2, the gas control device 16 of the inventioncomprises a hollow casing 20 made of any suitable material such as castbrass, consisting of a generally cup-shaped body 22 and aconcavely-shaped cap 24 in threaded engagement therewith. The casing 20is suitably fashioned to provide a cutting oxygen inlet 23 openingthrough a passage 3G in the cap 24 into a cutting oxygen dome or chamber32. The cutting oxygen finds outlet from dome 32 in a manner to beexplained hereinafter through a passage 34 to a cutting oxygen outlet36.

Admission of preheat oxygen into the body 22 occurs through a preheatoxygen inlet 38 connected with a preheat port or passage lit-40a whichtraverses a vertical bore 42. The preheat passage 40a terminates in anoutlet 44, through which delivery of the preheat oxygen is effected.

The dome 32 is divided into an upper section 46 and a lower section 48by means of an annular, flexible diaphragm 50, preferably made of rubberor a flexible sheet metal, which diaphragm is clampingly held at itsouter periphery between a shoulder 52 in cap 24 and a flange 54 in body22. A seal ring 58 may be employed to seal the joint. A slip ring 56 maybe employed to prevent damage to and twisting of the diaphragm whenthreading on the cap.

The center of the diaphragm 59 is closed by a valve 69 and a valve seat62 arrangement. The valve seat 62 is provided with a threadedcylindrical wall 64. The 'inner margin of diaphragm 5G is clampedbetween an annulus or diaphragm plate 66 and the valve seat 62 as bymeans of a clamping nut 68 in threaded engagement with the cylindricalwall 64. The valve 60 has a stem 70 which passes downwardly through acentral opening in the valve seat 62, and extends across the lower domesection 48 into the vertical bore 42. The stem 76 is provided with aconical tip or end 72 adapted to seat against a shoulder 74 in the bore42 and close the traversing preheat oxygen passageway 49-4012.Adjustment of the conical tip 72 to fully or partially, open or close,the passageway 4040a is accomplished by means of a preheat adjusting orlimiting member comprising a handle 76 having an elongated shank orlimit 78 threaded into the body 22 and adjustably extending into thebore 42 where it is adapted to engage the conical tip 72. Packing 79 maybe employed to hold the limit 78 in adjusted position. A suitable seal,such as an O-ring 81 carried by stem 70, seals the cutting oxygen in thedome 32 from the preheat oxygen in the passage 404-4la.

The valve 60 is held in closed position by a light spring disposedloosely about the stem 70 and exerting spring pressure against a springretainer 82 on said stem and the underside of the valve seat 62. Asecond spring 84 of larger diameter than spring 81 fitting loosely thecylindrical wall '64 of valve seat 62, and a recess 86 in the body 22will under all conditions permit sutficient opening of the Valve 66which in the present instance is accomplished by depression of the valveseat 62 against the forces of the springs 84 and 80. The springs 84- and80 may have any desired spring tensions, which tensions determineapproximately the differential in pressure on opposite sides of thediaphragm necessary to open the valve 60'. Opening of the valve 60enables cutting oxygen to flow through relatively large openings 88 invalve seat 62. A pin open ing or bleeder hole 90 in the valve 6% permitspressure equalization on both sides of the diaphragm 50 when the valveis closed.

In operation the blowpipe is prepared for service by first shutting allvalves at the blowpipe and then turning the handle 76 of the limit 78fully in, thereby limiting the vertical movement of the conical tip 72with respect to the shoulder 74 and fully opening the perheat port40-4ila to the flow of preheat oxygen issuing from preheat oxygen source14. At the same time, the stem '70 and the valve 69 are lifted acorresponding distance, along with the valve seat 62 and the diaphragmSit, by reason of the tension in the spring 84. After setting thedesired pressures atthe three regulators 13a, 13b, and

' 130, the blowpipe is is lighted and the resulting hot,

preheat flame adjusted by means of a preheat valve 92 and a fuel valve94- on the blowpipe 16. Thereafter, the cutting oxygen valve 96 at theblowpipe is opend, relieving the pressure in the lower section 48 of thedome 32 and causing a pressure differential to exist on opposite sidesof the diaphragm 5i Thereupon the force of the cutting oxygen pressureacting upon the upper surface of the diaphragm depresses the diaphragm,allowing cutting oxygen to flow through the valve seat openings 88 andthrough delivery passages 34 and 36 to the blowpipe 16, and establishinga substantially constant pressure differential in the dome 32corresponding approximately to the force necessary to overcome thetension in the springs 84 and 80.

Because of the relatively large size of the valve seat opening 88 andthe relatively small separation distance between the valve 60 and valveseat 62 required to establish the requisite pressure drop, thefunctioning of the diaphragm valve 6% is virtually independent of theamount of cutting oxygen flow therethrough. Consequently, a singlecutting oxygen valve 60 having a relatively constant pressure drop canbe used to supply a multiple cutting blowpipe setup without furtherchanges in the upstream pressure setting other than pressure dropscaused by the hose each time the number of blowpipes is changed.

The preheat flame which during this proceeding has remained unchangedbecause of the raised position of the conical tip 72 is now throttled toa soft flame by backing out limit 78, which action lowers the valve 60,valve seat 62, and diaphragm 50, as a unit, but does not afiect the flowof cutting oxygen past the valve 60 since the pressure differentialacross the diaphragm remains unchanged. Following this, the flow ofcutting oxygen is shut off at the blowpipe whereupon the Valve seat 62rises to close the cutting oxygen valve 60 and the pressure in the lowerdome section 48 becomes equalized with the pressure in the upper section46 by reason of the bleeder hole 90. Equalization of the pressure causesthe diaphragm 50 to rise to a stable or equilibrium position,

thereby raising the conical tip 72 and restoring a hot preheat flamecondition.

Upon resumption of the flow of cutting oxygen, the relief of thepressure on the underside of the diaphragm causes downward movement ofthe diaphragm and the conical end strikes the limit 78-, therebyautomatically adjusting the flow of preheat oxygen to the previouslyadjusted rate.

An obvious advantage of the invention is that once the preheat flamecontrol mechanism has been initially pressure diflierential across thediaphragm 50 is virtually independent of the quantity of cutting oxygenflow and remains substantially constant regardless of the number ofblowpipes serviced by the diaphragm valve 60.

From the above description it will therefore be seen that the presentinvention provides improved means for rapid and efiicient preheatingwhen cutting with an oxygen fuel gas cutting torch, which automaticallythrottles the preheat oxygen from a high flow for initial preheating toa normal working flow when the torch cutting oxygen valve is opened. Thereduction in the heating ability of the preheat flame during oxygencutting prevents kerf meltover and assures the production of clean,sharpedged cuts.

The preheat flame control apparatus of the invention is admirably suitedfor use with three-hose cutting blowpipes of the injector type suppliedfrom separate preheat oxygen, cutting oxygen, and fuel regulators, sincethe flow of preheat oxygen in the blowpipe automatically establishes theratio of fuel gas to preheat oxygen in the preheat flame gas mixture. Itshould be noted, however, the invention is also susceptible of use inconnection with blowpipes of the mixer and other types. In addition, theinvention can be installed and operated in all positions and can beoperated either at the blowpipe or back at the regulator station.Moreover, the shut-oft of cutting oxygen can be upstream or downstreamof the preheat flame control apparatus.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the invention.

What is claimed is:

l. A preheat oxygen control comprising a casing, a cutting oxygenchamber in said casing, a flexible diaphragm mounted across said cuttingoxygen chamber and having an aperture therein, inlet and outlet means onthe upper and lower sides of said diaphragm respectively for deliveringand discharging cutting oxygen, a valve construction mounted in theaperture of said daphragrn and including .a valve cooperating with avalve seat bounding the aperture of said diaphragm on the upper side ofsaid apertured diaphragm, said valve having a member extending throughsaid valve seat for reciprocal movement with said valve and having meansfor equalizing the pressures across said valve and means for constanttlyurging said valve to said valve seat, means in said casing forresiliently supporting said diaphragm and valve construction againstfree downward movement, a bore in said casing for receiving said valvemember, a preheat oxygen passage traversing said bore and sealed fromsaid cutting oxygen chamber, means provided on said valve membercooperating with said preheat oxygen passage to throttle the flow ofpreheat oxygen therethrough and adjustable means for stopping thedownward movement of said valve member means whereby preheat oxygen flowis controlled by cutting oxygen flow with a substantially constantpressure drop thereacross.

2. A preheat flame control device comprising a casing having a cuttingoxygen chamber therein, an apertured diaphragm mounted across saidcutting oxygen chamber, an inlet on one side of said diaphragm and anoutlet from said cutting oxygen chamber on the other side of saiddiaphragm, a valve construction including a valve having a bleeder holeand cooperating with a valve seat bounding the aperture of saiddiaphragm on said one side of said diaphragm, said valve having a stemextending through said aperture and valve seat, a spring acting betweensaid valve stem and diaphragm, constantly urging said valve to saidvalve seat, a conical tip provided on said valve stem, a spring means insaid casing for resiliently supporting said diaphragm against freedownward movement, a bore in said casing for receiving said valve stem,a preheat oxygen passage traversing said bore and cooperating with saidconical tip on said valve stem to throttle the flow of preheat oxygenthrough said preheat oxygen passage and means positioned in said borefor providing an adjustable stop for said conical tip on said valve stemwhereby preheat oxygen flow is controlled by cutting oxygen fiow with asubstantially constant pres sure drop across said diaphragm.

3. Apparatus according to claim 2, and a bleeder hole in said valve forequalizing the pressure across said diaphragm when the delivery ofcutting oxygen is stopped, whereby said spring means moves sm'd valveconstruction and automatically restores fill flow of preheat oxygen insaid passage.

4. Apparatus according to claim 2, said preheat oxygen control apparatusbeing for a single blowpipe.

5. Apparatus according to claim 2, said preheat oxygen control apparatusbeing for a multiple blowpipe setup.

6. A flow control device comprising a casing having an inlet and a firstcutting oxygen chamber for receiving cutting oxygen from said inlet anda second cutting oxygen chamber having a delivery outlet, cutting oxygenvalve means moveably mounted between said chambers, means associatedwith said valve means for equalizing the pressures across said valvemeans when there is no demand for oxygen, a preheat oxygen passagetraversing said casing and sealed from said first and second chambers, apreheat oxygen control valve associated with said cutting oxygen valvemeans to be moveable therewith and cooperating with said preheat oxygenpassage to obstruct the flow of preheat oxygen therethrough, and meansfor opening said cutting oxygen valve means and for controlling themovements of said preheat oxygen control valve when said valve meansmoves in response to the flow of cutting oxygen from said secondchamber.

7. A gas flow control device comprising a casing having an inlet and afirst cutting oxygen chamber for receiving cutting oxygen from saidinlet and a second cutting oxygen chamber having a delivery outlet forsupplying cutting oxygen to the point of use; a flexible diaphragmmounted between said chambers and having an aperture therein; valvemeans mounted in said apertured diaphragm to be moveable therewith andincluding means for equalizing the pressures across said valve meanswhen there is no demand for cutting oxygen; a preheat oxygen passagetraversing said casing and sealed from said first and second chambers; apreheat oxygen control valve associated with said cutting oxygen valvemeans to move therewith and cooperating with said preheat oxygen passageto obstruct the flow of preheat oxygen therethrough; means for limitingthe movement of said preheat oxygen control valve and opening said valvemeans when said diaphragm, valve means and preheat oxygen control valveare motivated by the delivery of cutting oxygen from said second cuttingoxygen chamber.

Reierences Cited in the file of this patent UNITED STATES PATENTS363,643 Jacobs May 24, 1887 498,897 Von Ey June 6, 1893 1,766,648 KellerJune 24, 1930 2,020,773 Ernst Nov. 12, 1935

